Two logic switches, one for each network:

()[root@overcloud-controller-0 /]# ovn-nbctl ls-list
e5bcc681-9bec-42b7-bedf-12ce8e9611de (neutron-2561f8db-e1c8-4185-9056-0883686a8a53)
0304d31c-f512-43bc-949e-4d45f754082c (neutron-9d4c5e96-bba6-4716-adb2-3d6c2ddd3903)


()[root@overcloud-controller-0 /]# ovn-nbctl show e5bcc681-9bec-42b7-bedf-12ce8e9611de
switch e5bcc681-9bec-42b7-bedf-12ce8e9611de (neutron-2561f8db-e1c8-4185-9056-0883686a8a53) (aka infra_external)
    port 9075cf11-d5e4-4e60-84f8-5dd38ff72833
        type: localport
        addresses: ["fa:16:3e:91:da:cc 172.20.10.70"]
    port e696d78b-13c4-4781-8bd5-f6a7db16daee
        type: router
        router-port: lrp-e696d78b-13c4-4781-8bd5-f6a7db16daee
    port provnet-2561f8db-e1c8-4185-9056-0883686a8a53
        type: localnet
        tag: 4
        addresses: ["unknown"]
    port 75a72825-0c32-4a86-8896-72b9cbfb6995
        addresses: ["fa:16:3e:47:ee:dd 172.20.10.201"]
()[root@overcloud-controller-0 /]# ovn-nbctl show 0304d31c-f512-43bc-949e-4d45f754082c
switch 0304d31c-f512-43bc-949e-4d45f754082c (neutron-9d4c5e96-bba6-4716-adb2-3d6c2ddd3903) (aka infra_internal)
    port b975d1ca-3b33-4177-bbcb-d07439f1638e
        type: localport
        addresses: ["fa:16:3e:be:97:a0 192.168.10.10"]
    port 65a28088-761c-461c-912c-7d0a3781ab6b
        type: router
        router-port: lrp-65a28088-761c-461c-912c-7d0a3781ab6b
    port 12427559-a937-4b50-a64c-aef54a3284d8
        addresses: ["fa:16:3e:7c:36:ff 192.168.10.102"]



()[root@overcloud-controller-0 /]# ovn-trace infra_internal 'inport == "12427559-a937-4b50-a64c-aef54a3284d8" && eth.src == fa:16:3e:7c:36:ff && ip4.src == 192.168.10.102 && eth.dst == fa:16:3e:be:97:a0 && ip4.dst == 1.1.1.1'
# ip,reg14=0x3,vlan_tci=0x0000,dl_src=fa:16:3e:7c:36:ff,dl_dst=fa:16:3e:be:97:a0,nw_src=192.168.10.102,nw_dst=1.1.1.1,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=0

ingress(dp="infra_internal", inport="124275")
---------------------------------------------
 0. ls_in_port_sec_l2 (ovn-northd.c:4516): inport == "124275" && eth.src == {fa:16:3e:7c:36:ff}, priority 50, uuid f869e22a
    next;
 1. ls_in_port_sec_ip (ovn-northd.c:4188): inport == "124275" && eth.src == fa:16:3e:7c:36:ff && ip4.src == {192.168.10.102}, priority 90, uuid ec3f6e49
    next;
 3. ls_in_pre_acl (ovn-northd.c:4706): ip, priority 100, uuid 8ca99cd5
    reg0[0] = 1;
    next;
 5. ls_in_pre_stateful (ovn-northd.c:4895): reg0[0] == 1, priority 100, uuid dd15ba61
    ct_next;

ct_next(ct_state=est|trk /* default (use --ct to customize) */)
---------------------------------------------------------------
 6. ls_in_acl (ovn-northd.c:5086): (!ct.trk || (!ct.new && ct.est && !ct.rpl && ct_label.blocked == 0)) && (inport == @pg_63bc7fdf_3061_410f_9e82_80278b987928 && ip4), priority 2002, uuid 655e4046
    next;
19. ls_in_l2_lkup (ovn-northd.c:6757): eth.dst == fa:16:3e:be:97:a0, priority 50, uuid e74c5d8a
    outport = "b975d1";
    output;

egress(dp="infra_internal", inport="124275", outport="b975d1")
--------------------------------------------------------------
 1. ls_out_pre_acl (ovn-northd.c:4708): ip, priority 100, uuid 79c0a63a
    reg0[0] = 1;
    next;
 2. ls_out_pre_stateful (ovn-northd.c:4897): reg0[0] == 1, priority 100, uuid 1de53e75
    ct_next;

ct_next(ct_state=est|trk /* default (use --ct to customize) */)
---------------------------------------------------------------
 9. ls_out_port_sec_l2 (ovn-northd.c:4582): outport == "b975d1", priority 50, uuid 2feba137
    output;
    /* output to "b975d1", type "localport" */



So from my physical router, which is the gateway device 172.20.0.254, I obviously just see the ARP's as well, but for completeness:

10:10:05.688409 fa:16:3e:d7:80:3a > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has 1.1.1.1 tell 172.20.10.107, length 46
10:10:06.712518 fa:16:3e:d7:80:3a > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has 1.1.1.1 tell 172.20.10.107, length 46


$ openstack port list | grep 3a
| ee54a5a3-0e4a-419a-9cbe-246d7a143874 |      | fa:16:3e:d7:80:3a | ip_address='172.20.10.107', subnet_id='bf21b56a-65c4-49fb-b345-b804c0429167'  | N/A    |